The use of sighting devices by hunters and marksmen has been known for centuries. Hunters and marksmen have long used sighting devices in order to accurately direct a projectile from a bow, pistol, rifle, or shotgun. Such sighting devices have evolved from simple mechanical devices which were aligned to the target to optical scopes with precision lenses and laser pointing devices.
A reflex sight (or red dot sight) is a sighting device which can be affixed to a bow, pistol, rifle, or shotgun, to assist in aligning the projectile with the intended target. In such devices, a dot of light, (traditionally red but other colors such as green are also available) is projected from a light sources (such as an LED) to a lens which is visible to the shooter who aligns the dot on the intended target. The dot is calibrated such that its alignment with the target also aligns the projected to the intended target. Such devices are commonly adjustable for distance (range), windage, and intensity (to accommodate various light conditions). However, as it is apparent, in order to adjust the sighting device for the proper range, one must first know the actual range to the target.
In order to determine range, many different types of range finding devices are known in the art. The presently most accurate type of devices are the electronic range finding devices. Electronic range finding devices produce a signal, most commonly a very fast pulse of laser light, directed at the target. A portion of the signal is reflected back toward the device which is then directed toward a receiving lens and a receiver. Microprocessor technology containing a high speed clock is used to calculate the distance (range) by measuring the time required for each pulse to travel from the device and back to the receiver.
At present, both the described sighting devices and range finding devices are separate units which must each be carried by the hunter/marksman. In other words, hunters and marksmen using a red dot sight (reflex sight) on their bows, pistols, rifles, or shotguns must also use another device for range finding to gauge the distance to their intended target. In the case of most hunting situations, when time is spent determining the distance to the game with one device and then additional time spent getting ready with the bow or firearm, often the game has moved thus negating the advantage of knowing the target's distance. A need, therefore, exists for an inclusive combination device which includes a red dot sight and an electronic range finding device in one unit.